<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style type="text/css">
        /* 比较数量 */
        /* div span strong {
            color: red;
        }
        div strong {
            color: blue;
        } */
        
        /* 比较标签 */
        /* div span strong {
            color: red;
        }
        .title strong {
            color: blue;
        } */

        /* 权重交大 */
        /* #top strong{
            color: pink;
        } */
        /* 相同比较距离 */
        .title span strong {
            color: blue;
        } 
        div .title strong {
            color: red;
        }
    </style>
</head>
<body>
    <div id="top">
        <div>
            <div class="title">
                <span>
                    <strong>1234</strong>
                </span>
            </div>
        </div>
    </div>
</body>
</html>